If Arshad earns ₹x per day and spends ₹y per day, then his saving for the month of March is

1. ₹(31x − y)

2. ₹31(x − y)

3. ₹31(x + y)

4. ₹31(y − x)

If the length of a rectangle is 3 times its breadth and the breadth is x units, then its perimeter is

1. 4x units

2. 6x units

3. 8x units

4. 10x units

For any two integers a and b, which of the following suggests that the operation of addition is commutative?

1. a × b = b × a

2. a + b = b + a

3. a − b = b − a

4. a + b > a

The number of unlike terms in the expression

2x²y − 3y²z − 5yx² + yz(x + y) + 7 is

1. 3

2. 4

3. 5

4. 6